Muffler

ABSTRACT

A muffler including an outer shell; an end plate that is laser-welded to the outer shell; a sheathing member that is provided on the outer side of the outer shell to sheath the outer shell with the sheathing member; and a shielding portion that prevents liquid from entering into the sheathing member through a clearance formed between the outer shell and the end portion of the sheathing member, at which the sheathing member is connected to the outer shell. Providing such shielding portion makes it possible to prevent liquid such as water from entering into the sheathing member through the clearance, because the shielding portion blocks such liquid. As a result, inconvenience due to entry of the liquid into the space is prevented, and connection between the sheathing member and the outer shell is secured.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2006-250687 filed on Sep. 15, 2006 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to the structure of a muffler provided to reduce exhaust noise of an in-vehicle internal combustion engine.

2. Description of the Related Art

A conventional muffler has end plates that are connected to middle portions of an exhaust pipe for an in-vehicle internal combustion engine and a cylindrical outer shell that supports the end plates, and reduces exhaust noise using the space defined by the end plates and the outer shell. The muffler is formed by laser-welding the outer shell and the end plates together, because laser-welding provides good workability during the assembly of the muffler (refer, for example, to Japanese Patent Application Publication No. 2005-155551 (JP-A-2005-155551)).

Also, as shown in FIG. 6, there is a conventional muffler in which a sheathing member “c” is provided, via glass wool c1, on the outer side (outer face) of an outer shell “a” provided with the end plate “b”. Such a structure is employed to maintain sufficient noise insulating properties.

However, in the conventional muffler described above, when the sheathing member “c” is connected to the outer face of the outer shell “a”, a slight clearance S is formed between the outer face of the outer shell “a” and the end portion of the sheathing member “c”, at which the sheathing member “c” is connected to the outer shell “a”. The clearance S is exposed to the outside. Accordingly, if liquid, for example, water enters, all at once, into the sheathing member “c” through the clearance S, for example, while the vehicle is running, connection between the sheathing member “c” and the outer shell “a” may loosen due to the liquid pressure produced when the liquid enters into the sheathing member “c”.

SUMMARY OF THE INVENTION

The invention provides a muffler having a simple structure which makes it possible to prevent liquid such as water from entering into a sheathing member through a clearance formed between the outer face of an outer shell and the end portion of the sheathing member, at which the sheathing member is connected to the outer shell, thereby preventing connection between the sheathing member and the outer shell from loosening.

An aspect of the invention relates to a muffler including an outer shell; an end plate that is laser-welded to the outer shell; a sheathing member that is provided on the outer side of the outer shell to sheath the outer shell with the sheathing member; and a shielding portion that prevents liquid from entering into the sheathing member through a clearance formed between the outer shell and the end portion of the sheathing member, at which the sheathing member is connected to the outer shell.

Providing such shielding portion makes it possible to prevent liquid such as water from entering into the sheathing member through the clearance, because the shielding portion blocks the liquid. As a result, connection between the sheathing member and the outer shell is secured.

With the muffler having such simple structure where only the shielding portion is provided, even when a vehicle suddenly runs into a puddle while running, the liquid such as water is blocked by the shielding portion. Thus, it is possible to reliably prevent the liquid from entering, all at once, into the sheathing member through the clearance, and, therefore, inconvenience due to such entry of the liquid such as water is prevented and connection between the sheathing member and the outer shell is secured.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, advantages thereof, and technical and industrial significance of the invention will be better understood by reading the following detailed description of an example embodiment of the invention, when considered in connection with the accompanying drawings, in which:

FIG. 1 is the plan view showing the structure of an exhaust pipe of a vehicle;

FIG. 2 is the partial cross-sectional view of a muffler provided with a shielding member according to an embodiment of the invention;

FIG. 3 is the cross-sectional view showing a shielding portion according to a first modified example of the embodiment of the invention;

FIG. 4 is the cross-sectional view showing a shielding portion according to a second modified example of the embodiment of the invention;

FIG. 5 is the cross-sectional view showing a shielding portion according to a third modified example of the embodiment of the invention; and

FIG. 6 is the cross-sectional view showing a part of the structure of a conventional muffler.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENT

In the following description and accompanying drawings, the invention will be described in more detail with reference to an example embodiment.

FIG. 1 is the plan view showing the structure of an exhaust pipe of a vehicle. A muffler 1 is provided at a position below a body of the vehicle and between exhaust pipes 3, 3 and an exhaust pipe 4. Two end plates 2, 2 are arranged on the front end and the rear end of the muffler 1, respectively. Namely, the muffler 1 is connected to the exhaust pipes 3, 3 and the exhaust pipe 4 via the respective end plates 2, 2 connected to an outer shell 11. The exhaust gas is introduced into the muffler 1 through the exhaust pipes 3, 3 (inlet pipes), and the exhaust gas introduced into the muffler 1 is discharged to the outside through the exhaust pipe 4 (outlet pipe). While the exhaust gas passes through the muffler 1, the energy of the exhaust gas is reduced in the muffler 1, and, therefore, the exhaust noise is reduced.

Hereafter, the structure of the muffler 1 according to the embodiment of the invention will be described in detail. As shown in FIG. 2, the outer shell 11 and the end plates 2, 2 are laser-welded together, because laser-welding provides good workability during the assembly of the muffler 1.

A sheathing member 5 is provided on the outer side of the outer shell 11. The space between the sheathing member 5 and the outer face of the outer shell 11 is filled with, for example, glass wool 51. Providing the sheathing member 5 on the outer side of the outer shell 11 with the space between the sheathing member 5 and the outer shell 11 filled with the glass wool 51 improves noise insulating properties, and minimizes thermal effects on peripheral members due to heat radiation.

More specifically, an upper and lower pair of members is used as the sheathing member 5. These two members are connected, at the end portions, to each other by “crimping” or “spot-welding”. At this time, the end portions are positioned at the side portions of the outer shell 11. As a result, the sheathing member 5 covers the outer face of the outer shell 11, as described above.

Accordingly, as a result of connecting these upper and lower members to each other, an annular clearance S is formed between the end portion of the sheathing member 5 and the outer shell 11.

A shielding member 6, serving as a shielding portion, is provided on the front side of the clearance S. The shielding member 6 is provided to prevent liquid such as water from entering into the sheathing member 5 through the clearance S, for example, when the vehicle suddenly runs into a puddle.

The shielding member 6 is fixed, at a front-end portion (base end portion) 61, to the front end plate 2 by appropriate connecting means, for example, welding. The shielding member 6 extends rearward while smoothly curving so that the rear-end portion (tip portion) of the shielding member 6 covers the clearance S formed between the outer face of the outer shell 11 and the front-end portion of the sheathing member 5. More specifically, the shielding member 6 is arranged so that a rear-end portion 62 overlaps the front-end portion of the sheathing member 5 by a predetermined length (L). Thus, the shielding member 6 covers the lower portion or the entire periphery of the front-end portion of the sheathing member 5. As a result, the clearance S is covered at the front.

The shielding member 6 may have a U-shape when viewed from the front so that the clearance S is covered up to a predetermined height from the bottom portion. Alternatively, the shielding member 6 may have an annular shape so that the entire periphery of the clearance S is covered.

With such simpler structure where only the shielding member 6 is arranged on the front side of the clearance S, even when the vehicle suddenly runs into a puddle while running, the liquid such as water is blocked by the shielding member 6. Thus, it is possible to reliably prevent the liquid from entering, all at once, into the sheathing member through the clearance S, and, it is, therefore, possible to prevent inconvenience due to entry of the liquid such as water into the sheathing member 5, and secure connection between the sheathing member 5 and the outer shell 11.

The shielding member 6, which is a separate member, is provided to the muffler 1. Accordingly, the shielding member 6 may be easily applied to any mufflers provided with the sheathing member 5.

FIG. 3 shows a shielding portion according to a first modified example of the embodiment of the invention. The shielding portion is formed of a bent portion 11 a that is formed by bending the front-end portion of the outer shell 11 so that the front-end portion protrudes outward in a substantially radial direction of the muffler 1. The clearance S is covered by the bent portion 11 a. Namely, the outer shell 11, which has the front-end portion that further extends frontward from the portion at which the outer shell 11 and the end plate 2 are laser-welded together, is used, and the bent portion 11 a is formed by bending the extension portion outward in a substantially radial direction of the muffler 1.

FIG. 4 shows a shielding portion according to a second modified example of the embodiment of the invention. The shielding portion is formed of an expanded portion 11 b formed by expanding the front-end portion of the outer shell 11 so that the front-end portion protrudes outward in a substantially radial direction of the muffler 1. The expanded portion 11 b covers the clearance S. Namely, the expanded portion 11 b is formed at the front-end portion of the outer shell 11 at a position on the front side of the front-end of the sheathing member 5. Then, the extension portion that extends frontward from the expanded portion 11 b is laser-welded to the end plate 2.

FIG. 5 shows a shielding portion according to a third modified example of the embodiment of the invention. The shielding portion is formed of a bent portion 2 a that is formed by bending the end portion of the end plate 2 so that the end portion protrudes outward in a substantially radial direction of the muffler 1. The clearance S is covered by the bent portion 2 a. Namely, the end plate 2, which has the end portion that further extends rearward from the portion at which the end plate 2 and the outer shell 11 are laser-welded together, is used, and the bent portion 2 a is formed by bending the extension portion outward in a substantially radial direction of the muffler 1.

The bent portion 11 a, the expanded portion 11 b or the bent portion 2 a serves as the shielding portion. With such structure, as in the case where the shielding member 6 is arranged, even if the vehicle suddenly runs into a puddle while running, liquid such as water is blocked by the shielding portion. Thus, it is possible to reliably prevent the liquid from entering, all at once, into the sheathing member through the clearance S, and, it is, therefore, possible to prevent inconvenience due to entry of the liquid such as water into the sheathing member 5, and secure connection between the sheathing member 5 and the outer shell 11.

In this case, the bent portion 11 a and the expanded portion 11 b are formed by processing the outer shell 11, and the bent portion 2 a is formed by processing the end plate 2. Accordingly, the shielding portion is formed without increasing the number of components.

As in the case of the shielding member 6, each of these shielding portions may have a U-shape so as to cover the clearance S up to a predetermined height, from the bottom portion, in the both side portions, or an annular shape so as to cover the entire clearance S.

While the invention has been described with reference to an example embodiment thereof, it is to be understood that the invention is not limited to the example embodiment and constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the example embodiment are shown in various combinations and configurations, which are exemplary, other combinations and configurations, including more, less or only a single element, are also within the scope of the invention.

For example, in the embodiment described above, the shielding portion is provided at the front portion of the muffler in order to cover the clearance formed at the front portion of the muffler. However, the position where the shielding portion is provided is not limited this. The shielding portion may be provided at the rear portion of the muffler so as to prevent liquid such as water from entering into the sheathing member through the clearance formed at the rear portion of the muffler. 

1. A muffler, comprising: an outer shell; an end plate that is laser-welded to the outer shell; a sheathing member that is provided on an outer side of the outer shell to sheath the outer shell with the sheathing member; and a shielding portion that prevents liquid from entering into the sheathing member through a clearance formed between the outer shell and an end portion of the sheathing member, at which the sheathing member is connected to the outer shell.
 2. The muffler according to claim 1, wherein the shielding portion is formed of a shielding member that is provided to the end plate so as to face the clearance.
 3. The muffler according to claim 2, wherein the shielding member is provided on an outer side of the end portion of the sheathing member so as to cover the end portion of the sheathing member without contacting the sheathing member.
 4. The muffler according to claim 3, wherein the shielding member has a U-shape, and is arranged so as to cover the end portion of sheathing member from a bottom portion of the end portion of the sheathing member up to a predetermined height in both side portions of the sheathing member.
 5. The muffler according to claim 3, wherein the shielding member has an annular shape, and is arranged so as to cover an entire periphery of the end portion of the sheathing member.
 6. The muffler according to claim 2, wherein the shielding member is formed of a bent portion that is formed by bending an end portion of the end plate so that the end portion of the end plate protrudes outward in a substantially radial direction of the muffler.
 7. The muffler according to claim 6, wherein the shielding member has a U-shape, and is arranged so as to cover the end portion of sheathing member from a bottom portion of the end portion of the sheathing member up to a predetermined height in both side portions of the sheathing member.
 8. The muffler according to claim 6, wherein the shielding member has an annular shape, and is arranged so as to cover an entire periphery of the end portion of the sheathing member.
 9. The muffler according to claim 1, wherein the shielding portion is formed of a shielding member that is provided to the outer shell so as to face the clearance.
 10. The muffler according to claim 9, wherein the shielding member is formed of a bent portion that is formed by bending an end portion of the outer shell so that the end portion of the outer shell protrudes outward in a substantially radial direction of the muffler.
 11. The muffler according to claim 10, wherein the shielding member has a U-shape, and is arranged so as to cover the end portion of sheathing member from a bottom portion of the end portion of the sheathing member up to a predetermined height in both side portions of the sheathing member.
 12. The muffler according to claim 10, wherein the shielding member has an annular shape, and is arranged so as to cover an entire periphery of the end portion of the sheathing member.
 13. The muffler according to claim 9, wherein the shielding member is formed of an expanded portion that is formed by expanding an end portion of the outer shell so that the end portion protrudes outward in a substantially radial direction of the muffler.
 14. The muffler according to claim 13, wherein the shielding member has a U-shape, and is arranged so as to cover the end portion of sheathing member from a bottom portion of the end portion of the sheathing member up to a predetermined height in both side portions of the sheathing member.
 15. The muffler according to claim 13, wherein the shielding member has an annular shape, and is arranged so as to cover an entire periphery of the end portion of the sheathing member. 